Regensburg 2004 – scientific programme

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O: Oberflächenphysik

O 37: Zeitaufgelöste Spektroskopie I

O 37.3: Talk

Thursday, March 11, 2004, 16:15–16:30, H36

Lifetimes of quasiparticle excitations in 4d transition metals Mo and Rh — •Alexander Mönnich, Daniela Bayer, Michael Bauer, and Martin Aeschlimann — Dep. of Physics, University of Kaiserslautern, D-67663 Kaiserslautern

The dynamics of excited electrons in metals are crucial for a detailed understanding of various chemical and physical phenomena on metal surfaces. It is already known that noble metals show a longer lifetime of quasiparticle excitations than transition metals due to the higher density-of-states around the Fermi level. But also the electron dynamics between different transition metals can exhibit significant divergences.

With the time resolved two-photon photoelectron spectroscopy (TR-2PPE) method we investigated the electron dynamics of Mo and Rh in an energy range up to 3 eV above the Fermi level. LMTO-RPG-GW calculations predict a surprising large difference between the averaged lifetimes of electron quasiparticles in the 4d transition metals Mo and Rh [1] that were confirmed in our experiment. The characteristics of electronic structure responsible for energy dissipation processes of hot electrons will be discussed.

[1] V. P. Zhukov, F. Aryasetiawan, E. V. Chulkov, P. M. Enchenique PRB 65 11511 (2002)